/*
 * @(#)ByteToCharDBCS_ASCII.java	1.10 06/10/10
 *
 * Copyright  1990-2008 Sun Microsystems, Inc. All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation. 
 * 
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License version 2 for more details (a copy is
 * included at /legal/license.txt). 
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA 
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions. 
 *
 */
package sun.io;

public abstract class ByteToCharDBCS_ASCII extends ByteToCharConverter {
    private boolean savedBytePresent;
    private byte    savedByte;
    protected String  singleByteToChar;
    protected boolean leadByte[];
    protected short   index1[];
    protected String  index2;
    protected int     mask1;
    protected int     mask2;
    protected int     shift;
    public ByteToCharDBCS_ASCII() {
        super();
        savedBytePresent = false;
    }

    public int flush(char[] output, int outStart, int outEnd)
        throws MalformedInputException {
        if (savedBytePresent) {
            reset();
            badInputLength = 0;
            throw new MalformedInputException();
        }
        reset();
        return 0;
    }

    /**
     * Character conversion
     */
    public int convert(byte[] input, int inOff, int inEnd,
        char[] output, int outOff, int outEnd)
        throws UnknownCharacterException, MalformedInputException,
            ConversionBufferFullException {
        int inputSize;
        char    outputChar = '\uFFFD';
        charOff = outOff;
        byteOff = inOff;
        while (byteOff < inEnd) {
            int byte1, byte2;
            int v;
            if (!savedBytePresent) {
                byte1 = input[byteOff];
                inputSize = 1;
            } else {
                byte1 = savedByte;
                savedBytePresent = false;
                inputSize = 0;
            }
            if (byte1 < 0)
                byte1 += 256;
            if (!leadByte[byte1]) {
                outputChar = singleByteToChar.charAt(byte1);
            } else {
                if (byteOff + inputSize >= inEnd) {
                    savedByte = (byte) byte1;
                    savedBytePresent = true;
                    byteOff += inputSize;
                    break;
                }
                byte2 = input[byteOff + inputSize];
                if (byte2 < 0)
                    byte2 += 256;
                inputSize++;
                // Lookup in the two level index
                v = byte1 * 256 + byte2;
                outputChar = index2.charAt(index1[((v & mask1) >> shift)] + (v & mask2));
            }
            if (outputChar == '\uFFFD') {
                if (subMode)
                    outputChar = subChars[0];
                else {
                    badInputLength = inputSize;
                    throw new UnknownCharacterException();
                }
            }
            if (charOff >= outEnd)
                throw new ConversionBufferFullException();
            output[charOff++] = outputChar;
            byteOff += inputSize;
        }
        return charOff - outOff;
    }

    /**
     *  Resets the converter.
     */
    public void reset() {
        charOff = byteOff = 0;
        savedBytePresent = false;
    }
}
